This invention relates to a method for forming a thin film by means of a sputtering technique and more particularly to a method suitably used to form an alloy thin film, compound thin film or multi-layer thin film. This invention also relates to a sputtering device for forming such a thin film.
When forming an alloy thin film, compound thin film or laminated or multi-layer thin film by means of a sputtering technique, sputtering is generally carried out using an alloy target, compound target or laminated target. However, in the case where the alloy thin film is formed, some combinations of components of the alloy do not provide an alloy target of a uniform composition so that sputtering using this alloy target in turn does not provide an alloy thin film of a uniform composition. Further, in the case of the laminated target, some combinations of components do not permit a laminated structure to be formed or laminated structures made of some combinations of components can not be machined into a target. For example, it is very difficult to form a laminated structure target consisting of ceramics and metals.
There has been proposed in Japanese Patent Unexamined Publication No. 60-13,068 a method for forming a composite thin film such as a compound thin film, laminated thin film, etc. using plural targets in such a manner that sputtering is always carried out from one of the plural target with the other remaining targets interrupted by a shutter. This method, however, is not suitable to provide an alloy thin film of a uniform composition since vaporized particles produced from the respective targets are laminarly deposited on a substrate or wafer. The resultant film has a disadvantage that it provides a weak adhesion between the adjacent layers of the laminated film.